Process for the manufacture of a liquid detergent composition comprising a sulphiting agent and an enzyme system

ABSTRACT

A process is disclosed for the manufacture of a liquid detergent composition comprising a sulphiting agent and an enzyme system. Said enzyme system and said sulphiting agent interact together so as to generate odors which result in an odor deviation in said detergent composition. In the process of the invention, said enzyme system and said sulphiting agent are intimately mixed together separately from the remainder of the detergent composition so as to generate said odors outside the remainder of said detergent composition. Also disclosed is an enzyme premix consisting essentially of said enzyme system and said sulphiting agent.

TECHNICAL FIELD

The present invention relates to the manufacture of liquid detergentcompositions which comprise a sulphiting agent and an enzyme system.

BACKGROUND

Liquid detergents have been described extensively in the art. Inapplicants' co-pending European patent application 91870175.6 liquidlaundry detergents are described which comprise a sulphiting agent thatstabilizes the color characteristics of said compositions.

A new technical problem has occurred upon using sulphiting agents inliquid detergents in that important odors are generated as thesulphiting agent is incorporated in said detergents, so that saiddetergent's odor significantly deviates from its defined standard. Theproblem the present invention seeks to solve is to avoid odor deviationsin liquid laundry detergents which comprise sulphiting agents.

In response to this technical problem, applicants have found that saidodor deviation is generated by an interaction between the sulphitingagent and the enzyme which is also present in said detergent. Withoutwanting to be bound by theory, it is believed that the sulphiting agentreacts with impurities which are typically present in commerciallyavailable enzyme preparations.

Thus to avoid odor deviations in a liquid detergent comprising an enzymesystem and a sulphiting agent, the present invention proposes tointimately mix said enzyme system and said sulphiting agent apart fromthe remainder of said detergent composition.

Liquid detergent compositions comprising sulphiting agents have beendescribed in DE 3729474, EP 80 748, EP 80 223, EP 79641, BE 796 115 andU.S. Pat. No. 3,741,901. None of these documents suggest that enzymesand sulphiting agents may generate odor if they are mixed together.Furthermore, J01256596 (abstract) addresses the control ofenzyme-originating odors. In the context of this document, sulphites areused to diminish the odor of enzymes.

SUMMARY OF THE INVENTION

The present invention includes a process for the manufacture of a liquiddetergent composition comprising a sulphiting agent and an enzymesystem, whereby said enzyme system and said sulphiting agent interacttogether so as to generate odors, characterized in that said processincludes the steps of:

intimately mixing said enzyme system and at least a portion of saidsulphiting agent separately from the remainder of said detergentcomposition so as to generate said odor outside the remainder of saiddetergent composition, and

leaving said sulphiting agent and said enzyme system to interact in suchconditions and until said odor has disappeared or is substantiallyreduced, and

thereafter adding said intimate mixture of said sulphiting agent andsaid enzyme system to the remainder of said detergent composition.

The present invention further includes an enzyme premix obtainable inthe course of the process according to the present invention, saidenzyme premix consisting essentially of said enzyme system and saidsulphiting agent.

DETAILED DESCRIPTION OF THE INVENTION

The present invention concerns the manufacture of liquid detergentcomposition. Liquid detergent compositions manufactured according to thepresent invention comprise conventional detergency ingredients, anenzyme system and a sulphiting agent.

As used herein, conventional detergency ingredients include suchingredients as surfactants, builders, bleaches, solvents, soil releaseagents, color care ingredients, chelants, dyes, perfumes and the like.The detergent compositions herein may be aqueous or anhydrous, and canfurther be formulated as so-called concentrated liquid detergentcompositions. The detergent compositions according to the presentinvention can be formulated in a variety of different embodiments,especially laundry detergents.

The compositions manufactured according to the present invention furthercomprise a sulphiting agent. As used herein, sulphiting agents arecompounds capable of yielding sulfite ions in said liquid detergentcompositions. Such sulphiting agents include sulphite, hydrogenosulphiteor pyrosulphite salts, sulfur dioxide and sulfurous acid, or mixturesthereof. Preferred for use herein are alkali metal sulphites,pyrosulphite or hydrogenosulphite, particularly potassium sulphites. Thecompositions manufactured according to the present invention comprisefrom 0.01% to 1% by weight of said total composition of said sulphitingagent, preferably from 0.05% to 0.7%, most preferably from 0.1% to 0.5%.As used herein, the term sulphiting agents includes mixtures ofsulphiting agents.

The compositions manufactured according to the present invention furthercomprise an enzyme system. Said enzyme system includes protease,amylase, cellulase and lipase. As used herein, the term enzyme systemincludes single enzymes and mixtures thereof. Most commerciallyavailable enzymes come as preparations which comprise pure enzyme andimpurities. It is believed that said impurities interact with thesulphiting agents to generate odors. Accordingly, the term "enzyme" asused herein refers to the enzyme together with the impurities which comewith it. The present invention is only applicable to those enzymes, orenzyme preparations, which generate odors as they are intimately mixedwith a sulphiting agent as described hereinabove. Such enzymes includecommercially available Termamyl® and Maxamyl®. Detergent compositionsmanufactured according to the present invention comprise from 0.1% to10% by weight of said enzyme system, preferably from 0.2% to 5%, mostpreferably from 0.5% to 3%.

The process according to the present invention comprises at least threesteps.

In the first of these three steps, said sulphiting agent and said enzymesystem are intimately mixed together apart from the remainder of saidliquid detergent composition. As a result, during this first step saidodor is generated outside the remainder of the detergent composition assaid sulphiting agent and said enzyme system are intimately mixedtogether. By "intimately mixed" it is to be understood that saidsulphiting agent and said enzyme system are mixed so as to ensurecomplete interaction between both ingredients, thus complete generationof said odor. In the present invention, it is possible to mix saidenzyme system with the totality of the sulphiting agent to be formulatedin the detergent composition, or only a portion thereof. In any case,said enzyme system must be intimately mixed with at least a portion ofsaid sulphiting agent, wherein said portion of sulphiting agentrepresents a quantity which is sufficient to ensure complete generationof said odor. In practice, it has been noted that a very small quantityof sulphiting agent (see description of premix hereinafter) is requiredto completely generate said odor.

In the second step of the process according to the present invention,said sulphiting agent and said enzyme system are left to interact inappropriate conditions and until said odor has disappeared or issubstantially reduced. In practice it appears sufficient to gently mixboth ingredients under adequate aeration.

In the third step of the process according to the present invention,said intimate mixture of said sulphiting agent and said enzyme system isadded to the remainder of said liquid detergent composition. It is to beunderstood that said intimate mixture can also be added to a portion ofthe remainder of said liquid detergent composition, which in turn may beadded to a further portion of said liquid detergent composition or theremainder thereof.

The present invention further includes an enzyme premix obtainable inthe course of the process according to the present invention. Saidpremix consists essentially of said enzyme or mixtures thereof and saidsulphiting agent or mixtures thereof. By "subtantially", it is meantherein that said premix also comprises impurities which come with theenzyme raw material and which interact with said sulphiting agent. Saidpremix preferably comprises from 0.1% to 5% by weight of said premix ofsaid sulphiting agent, preferably from 0.1% to 1% by weight, theremainder of said premix being constituted by the enzyme raw material.

The present invention is further illustrated by the following example.

EXAMPLE

A liquid detergent composition is made which comprises the listedingredients in the listed proportions (weight %):

    ______________________________________                                        Linear Alkyl Benzene sulphonate                                                                   19.00                                                     Nonionic surfactant 12.00                                                     Fatty acid          11.00                                                     Citric acid         5.00                                                      Termamyl ® (1)  0.14                                                      Potassium sulphite  0.13                                                      Borate              2.50                                                      Calcium chloride    0.02                                                      Soil release aqent  0.45                                                      Brightener          0.15                                                      Chelant             1.00                                                      Ethanol             1.00                                                      Propanediol         11.00                                                     Monoethanolamine    9.50                                                      Potassium hydroxide 1.50                                                      Sodium hydroxide    1.80                                                      Minors and water    up to 100%                                                ______________________________________                                         (1) Termamyl ® is a commercially available amylase.                  

A premix comprising a portion of the potassium sulphite and theTermamyl® is prepared by intimately mixing 99.8 g of Termamyl whichcomes as a liquid raw material) with 0.2 g of K₂ SO₃ powder until the K₂SO₃ powder is dissolved into the liquid enzyme raw material. The odor isgenerated instantaneously. Said premix of Termamyl® and potassiumsulphites is mixed gently in an open container. After 48 hours, the odorgenerated as both ingredients were contacted disappears.

0.15 g of said premix is then added to the total remainder of saiddetergent composition (which includes the remainder of potassiumsulphite) by gently mixing both in a beaker at room temperature.

The liquid detergent composition described above was thus generated andexhibited no odor deviation. For comparison, the same detergentcomposition was manufactured where the enzyme preparation was addedwithout having been premixed with the sulphiting agent. Under theseconditions, a strong odor deviation was generated.

What is claimed is:
 1. A process for the manufacture of a liquiddetergent composition comprising a sulphiting agent and at least oneliquid enzyme whereby said at least one enzyme and said sulphiting agentinteract together so as to generate odors, characterized in that saidprocess includes the steps of:intimately mixing in liquid form said atleast one enzyme and at least a portion of said sulphiting agentseparately from the remainder of the liquid detergent composition so asto generate said odors outside the remainder of said liquid detergentcomposition, leaving said sulphiting agent and said at least one enzymeto interact until said odor has disappeared or is substantially reduced,and thereafter adding said intimate mixture of said sulphiting agent andsaid at least one enzyme to the remainder of the liquid detergentcomposition.
 2. A process according to claim 1 wherein said sulphitingagent is potassium sulphite.
 3. A process according to claim 1, whereinsaid intimate mixture comprises 0.1 to 5% by weight of the sulphitingagent.
 4. A process according to claim 1, wherein said intimate mixturecomprises 0.1 to 1% by weight of the sulphiting agent.
 5. A processaccording to claim 1, wherein said intimate mixture consists essentiallyof the at least one enzyme and 0.1 to 5% by weight of the sulphitingagent.
 6. A process according to claim 1, wherein said intimate mixtureconsists essentially of the at least one enzyme and the sulphitingagent.
 7. A process according to claim 1 wherein the reduction of saidodor is facilitated by mixing and aerating the intimate mix of enzymeand sulphiting agent.
 8. A process according to claim 1 wherein said,enzyme includes protease, amylase, cellulase, lipase, or mixturesthereof.
 9. A process according to claim 1 wherein said liquid detergentcomprises from 0.1 to 10% by weight of the enzyme.